/**
 * @author zz85 / http://www.lab4games.net/zz85/blog
 *
 * Two pass Gaussian blur filter (horizontal and vertical blur shaders)
 * - described in http://www.gamerendering.com/2008/10/11/gaussian-blur-filter-shader/
 *   and used in http://www.cake23.de/traveling-wavefronts-lit-up.html
 *
 * - 9 samples per pass
 * - standard deviation 2.7
 * - "h" and "v" parameters should be set to "1 / width" and "1 / height"
 */

THREE.HorizontalBlurShader = {

	uniforms: {

		"tDiffuse": { type: "t", value: null },
		"h":        { type: "f", value: 3.0 / 512.0 }

	},

	vertexShader: [

		"varying vec2 vUv;",

		"void main() {",

			"vUv = uv;",
			"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",

		"}"

	].join("\n"),

	fragmentShader: [

		"uniform sampler2D tDiffuse;",
		"uniform float h;",

		"varying vec2 vUv;",

		"void main() {",

			"vec4 sum = vec4( 0.0 );",
			"float lef4 = vUv.x - 4.0 * h;",
			"float lef3 = vUv.x - 3.0 * h;",
			"float lef2 = vUv.x - 2.0 * h;",
			"float lef1 = vUv.x - 1.0 * h;",
			"float rig1 = vUv.x + 1.0 * h;",
			"float rig2 = vUv.x + 2.0 * h;",
			"float rig3 = vUv.x + 3.0 * h;",
			"float rig4 = vUv.x + 4.0 * h;",
			
			"lef4 = lef4 >= 0.0 ? lef4 : (1.0 + lef4);",
			"lef4 = lef4 < 1.0  ? lef4 : (lef4 - 1.0 );",
			"lef3 = lef3 >= 0.0 ? lef3 : (1.0 + lef3);",
			"lef3 = lef3 < 1.0  ? lef3 : (lef3 - 1.0 );",
			"lef2 = lef2 >= 0.0 ? lef2 : (1.0 + lef2);",
			"lef2 = lef2 < 1.0  ? lef2 : (lef2 - 1.0 );",
			"lef1 = lef1 >= 0.0 ? lef1 : (1.0 + lef1);",
			"lef1 = lef1 < 1.0  ? lef1 : (lef1 - 1.0 );",
			"rig1 = rig1 >= 0.0 ? rig1 : (1.0 + rig1);",
			"rig1 = rig1 < 1.0  ? rig1 : (rig1 - 1.0 );",
			"rig2 = rig2 >= 0.0 ? rig2 : (1.0 + rig2);",
			"rig2 = rig2 < 1.0  ? rig2 : (rig2 - 1.0 );",
			"rig3 = rig3 >= 0.0 ? rig3 : (1.0 + rig3);",
			"rig3 = rig3 < 1.0  ? rig3 : (rig3 - 1.0 );",
			"rig4 = rig4 >= 0.0 ? rig4 : (1.0 + rig4);",
			"rig4 = rig4 < 1.0  ? rig4 : (rig4 - 1.0 );",

			"sum += texture2D( tDiffuse, vec2( lef4, vUv.y ) ) * 0.051;",
			"sum += texture2D( tDiffuse, vec2( lef3, vUv.y ) ) * 0.0918;",
			"sum += texture2D( tDiffuse, vec2( lef2, vUv.y ) ) * 0.12245;",
			"sum += texture2D( tDiffuse, vec2( lef1, vUv.y ) ) * 0.1531;",
			"sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y ) ) * 0.1633;",
			"sum += texture2D( tDiffuse, vec2( rig1, vUv.y ) ) * 0.1531;",
			"sum += texture2D( tDiffuse, vec2( rig2, vUv.y ) ) * 0.12245;",
			"sum += texture2D( tDiffuse, vec2( rig3, vUv.y ) ) * 0.0918;",
			"sum += texture2D( tDiffuse, vec2( rig4, vUv.y ) ) * 0.051;",
			"if (h > 0.0){",
			"	vec4 srcValue = texture2D( tDiffuse, vec2( vUv.x, vUv.y ) );",
			"	sum = srcValue + srcValue - sum;",
			"}",
			"gl_FragColor = sum;",
			//"gl_FragColor = vec4(1,0,0,1);",

		"}"

	].join("\n")

};